Cabled and cableless interface method for connecting units within a rack

ABSTRACT

A system and method for automatically determining a physical location of one or more units in a rack, including: using one or more physical cables between rack units; cascading a first signal through the one or more units located in the rack, the first signal being encoded with a unit number and a physical parameter; and creating a rack ID by utilizing hardware parameters, the hardware parameters being determined by: detecting a second signal that exists from a bottom unit, the bottom unit located at the bottom of the rack; and using a third signal to send data between the one or more units in the rack by manipulating void spaces within the rack, the third signal being either cabled or an optical signal.

TRADEMARKS

IBM® is a registered trademark of International Business MachinesCorporation, Armonk, N.Y., U.S.A. Other names used herein may beregistered trademarks, trademarks or product names of InternationalBusiness Machines Corporation or other companies.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to connecting units within a rack, andparticularly to a method for automatically determining the physicallocation of units in a rack and creating a rack ID.

2. Description of Background

There are several problems concerning existing approaches fordetermining unit locations within a rack. Known methods that have beenused for location of Server and IT Equipment within a rack have beenmanual, e.g., entering the rack ID and location in the rack, enteringthe number wheels for rack location, and entering rack numbers orjumpers that assign a location number. A rack ID would be designated bya signal that would allow rack units to read a rack ID. However, thistechnique requires an external unit that contains a unique rack ID anddoes not address the location of units in a rack.

Considering the above limitations, it is desired to have a method forautomatically determining the physical location of units in a rack andcreating a rack ID.

SUMMARY OF THE INVENTION

The shortcomings of the prior art are overcome and additional advantagesare provided through the provision of a system comprising: a rack havingone or more units for automatically determining a physical location ofthe one or more units within the rack by implementing the steps of:using one or more physical cables between rack units; cascading a firstsignal through the one or more units located in the rack, the firstsignal being encoded with a unit number and a physical parameter; andcreating a rack ID by utilizing hardware parameters, the hardwareparameters being determined by: detecting a second signal that existsfrom a bottom unit, the bottom unit located at the bottom of the rack;and using a third signal to send data between the one or more units inthe rack by manipulating void spaces within the rack, the third signalbeing either cabled or an optical signal.

The shortcomings of the prior art are overcome and additional advantagesare provided through the provision of a method for automaticallydetermining a physical location of one or more units in a rack, themethod comprising: using one or more physical cables between rack units;cascading a first signal through the one or more units located in therack, the first signal being encoded with a unit number and a physicalparameter; and creating a rack ID by utilizing hardware parameters, thehardware parameters being determined by: detecting a second signal thatexists from a bottom unit, the bottom unit located at the bottom of therack; by manipulating void spaces within the rack, and using a thirdsignal to send data between the one or more units in the rack, the thirdsignal being either a cabled or an optical signal.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention. For a better understanding of the invention with advantagesand features, refer to the description and the drawings.

Technical Effects

As a result of the summarized invention, technically we have achieved asolution for a method for automatically determining the physicallocation of units in a rack and creating a rack ID.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a schematic diagram of a 42U rack that is loaded with 10 unitsof different sizes, each unit including cabled inputs and outputs, inaccordance with an embodiment of the invention;

FIG. 2 is a back end of one unit of FIG. 1 depicting two connectors;

FIG. 3 is a table illustrating the information contained in aninformation processor;

FIG. 4 is a table illustrating string data;

FIG. 5 is a schematic diagram of a 42U rack that is loaded with 10 unitsof different sizes, each unit including optical inputs and outputs, inaccordance with an embodiment of the invention;

FIG. 6 is a schematic diagram of how the optical links in FIG. 5 usevoid spaces in the sides of the rack, in accordance with an embodimentof the invention;

FIG. 7 is a schematic diagram of another method of producing an opticallink at a fixed x-y location in a unit, in accordance with an embodimentof the invention; and

FIG. 8 is a schematic diagram of where each rack unit or optical armcould have both a transmitter and a receiver on the top of the unit, inaccordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the exemplary embodiments is a method for units in a rackto determine their location in the rack without using manual detectingtechniques. Another aspect of the exemplary embodiments is utilizingsystem hardware parameters to create a unique rack ID. Another aspect ofthe exemplary embodiments is a method of determining a physical locationin a rack by summing up the number of U's in a Daisy chain method.Another aspect of the exemplary embodiments is a method for cablelessinterface between units stacked in a rack using void spaces in the sidesof racks, a method for cableless interface between units stacked in arack using the void spaces in the sides of racks, and a method forcableless interface between units stacked in a rack using a fixed x-ylocation for using optical transmitters and receivers.

In the exemplary embodiments of the present invention, a rack ID iscreated by using information from a bottom unit (e.g., racks that areloaded from the bottom up). Each unit stores its unit height in “Us,”and a cabling method where each box communicates to the box above it.The bottom unit sends a signal that it is box 1, and is “xUs high+1” andthe unique rack ID that it has created to the box above it. The nextunit adds one to the box number, so that box 2 knows that it starts atthe “xUs” high location, and knows what box number it is. This box thensends it up to the next unit up and so on. Every unit then knows the Unumber that it is mounted in, the number unit it is in the rack and hasa rack location. The exemplary embodiments are described with referenceto the figures and describe the above-mentioned features.

Referring to FIG. 1, a schematic diagram of a 42-unit high (42U) rack 10that is loaded with ten units of different sizes is illustrated. The 42Urack 10 of FIG. 1 includes at least a first unit 12 (10-6U) and a secondunit 14 (9-4U). Each unit includes at least two connectors. For example,unit 6-4U includes a first connector 16 and a second connector 18.

Referring to FIG. 2, a back end 20 of a unit depicting two connectors isillustrated. Each unit has two connectors as shown in FIG. 2: an “out”connector 22 and an “in” connector 24. There are 3 pins on the “in”connector 22, which include a ground pin, a serial in pin, and a pin toindicate location 1, which is used to distinguish the bottom unit andindicate that it is unit 1. The “out” connector 24 has a ground pin anda serial out pin. It will be noted that additional pins could be used ifa 2 or 3 wire serial bus is used. Moreover, included inside each unit isan information processor 26 and a service processor 28. In addition,FIG. 2 illustrates cables used to connect between units. Cable 30 is astandard cable used between the units, whereas and cable 32 is only usedin the first unit to instruct it that it is the unit in the bottom ofthe rack. However, the jumper in cable 32 is only required if a cablebreak function is desired. If cable 32 is not used, the unit with noserial inputs is the unit that becomes unit 1, the bottom unit in therack.

The information processor 26 stores and sends the following information:Unit ID, Rack ID, Number of Us, Number of blank Us above, U location,Number location and Fault status. This information is defined asfollows:

Unit ID: Unique ID for a unit, e.g., model number+serial number.

Rack ID: the Unique ID from Unit 1 used as rack ID.

Number of Us: the height of the Unit in Us.

Number of Blank Us: Field that can be loaded from an operating system toaccount for blank space in the rack, or units that don't support thisinterface.

U location: for first unit with this interface, if not 1, to deal withunits with no interface below the first unit with this interface.

Unit number: of first unit with this interface, if not 1 to deal withunits with no interface below the first unit with this interface.

U location: the location the unit starts at.

Number in the Rack: the unit number it is in the rack.

Fault status: fault status information being passed up.

This method is not limited to only this type of information. Theinformation is presented for illustrative purposes. One skilled in theart may use several different parameters and different values to achievesimilar results.

Referring to FIG. 3, a table 40 has been constructed to illustrate theinformation contained in the information processor 26 of FIG. 2. Thetable shows a simple ID A1 through AB, instead of the “modelnumber+serial number” that would be used in a real application. Thefirst unit has the cable 32 from FIG. 2 plugged into the “in” connector.This instructs the unit that it is the bottom unit, with the “number 1”pin grounded. Therefore, the bottom unit reads (from an onboardprocessor or from a Virtual Private Database (VPD) module) its ownunique ID (A1) and its own height (in Us). Also, the bottom unit storesin a storage unit that it is “Unit 1” and that it is in U location “1.”Note that if the drawer is the bottom drawer, but is not in U location“1,” this is overridden by the operating system. If no operating systemU value has been received by the unit, it defaults to U location “1.”

Unit 1 then Sends the following information, Rack Number A1, Unit number1, and U location 5 (location 1U+4U). Unit 2 receives this information,and writes the following information to its own onboard processor or itsown VPD module: the Rack ID of A1, Unit number 2 (Unit data 1+1) and Ulocation of 5. Unit 2 then sends to the next unit up in the rack, therack ID of A1, Unit number 2, and U location of 9 (5+4) and so on up therack. The data is then sent out at a fixed amount of time, to make surethat any new hardware that is added is detected. The service processor28 or other communication path to the operating system can now read thedata that is stored in each unit, where physical location with in a rackand a rack ID can be read.

The field call “Blank Us” is used in the case a blank “Us” is in themiddle of the rack between units. A system manager function coulddownload the blank number of Us to the unit under the blanks, thusassuring the rest of the units have the correct U location. These fields(i.e., U location and Unit number) are used by the first unit, so thatif there are units below this unit, they can be accounted for by havingthe system load these fields to account for units that do not supportthis interface. Therefore, if the first unit that uses this interface isat U5, and there are two 2 Units below it without this interface, thenumber 3 is loaded at the unit number, and 5U is loaded as the startpoint. Also if a unit, other then Unit 1, does not receive data after aspecified timeout, it does not change its stored data and continues tosend the old data to the next box, along with status of a cable break.All units above the break realize the cable break, and the first unitafter the cable break reports it to the system so that the cable breaklocation is known. Cable break detection is enabled by using cable 32 asshown in FIG. 2.

If there is a cable break at first power up, other methods may be used.Nevertheless, the cable break location is known, i.e., at a unit, butthe physical to logical location is not determined at that time. Theunits after the break could do one of 3 things for rack ID: (1) Use it'sUnit ID as the Rack ID, (2) Send the Unit ID of the first unit after thebreak as the rack ID to the units above, (3) Send blank Rack ID so thatit is know that the units location has not been mapped to a rack.However, once rack ID has been associated with the Unit, a cable breakshould not be allowed to change the rack ID that is stored, until thecable link is restored, and then the rack ID can be change if required(i.e., in a new rack or replacement of the bottom unit). When the cableis broken to add a new unit to the rack, the units above the break donot change the data and rack ID remains the same, as well as “numberlocation” and “U location.” When the new units are placed back in thestring, at this point new data begins to flow, and the data is updated.Each unit sees new data and knows if it has been moved in a rack, to anew rack or new hardware has been added.

An exemplary data string may include: (<Rack ID> <Location number> <Ulocation><Fault data, fault and indicate>). The information that is nowstored in each unit can be associated with that unit, so that if thesystem has a logical link to the unit, bus address, Small ComputerSystem Interface (SCSI) bus address, or other. This can now beassociated with the physical location. Thus, a physical to logicalassociation is now known. This data can now be used from the managementsystem to create a system visualization where a drawing of multiple racksystems can be created that shows both physical and logical locations.

There are some additional features that could be added to theseexemplary embodiments. One of these features is a rack indicator. Eachunit could also send in the serial string “Fault” and “Indicate”information in the serial string. This information would read and bepassed through each unit. A Rack Indicator could be placed on the top ofthe rack that would read this fault status (combination of all units inthe rack) and Light up a Light Emitting Diode (LED) with the correctstatus. It could also display the rack ID, if this feature was desired.

Another feature is related to string data. Referring to FIG. 4, a table42 has been constructed to illustrate the string data. String data couldbe sent up the rack. Where all data is sent upward through the rack,Unit 1 sends it is Rack A1, Unit 1 in rack location 1, and an unit ID ofA1, unit two adds unit 2, in location 5 with ID of A2 and so on. Thisway, the top unit in the system has complete information of all units inthe rack.

Another feature is related to a loop method. This could be realized witha total closed loop where the top unit wires back to the input of unit1. Unit 1 still has the grounded pin to instruct it that it is Unit 1.The string data would continue around the loop, until Unit 1 sees itsown data, and then would send the same string upward. The data wouldremain the same until a new unit was added where the units could detectthe difference. The string in the loop is called the hardware string. Anexemplary data string of this type may include: (<Rack ID> <Locationnumber> <U location> <Fault data, fault and indicate> <Hardwarestring>).

Another exemplary embodiment concerns an optical cable free method. Thisinvolves a way that units in a rack can send information to each otherwithout the use of cables. In particular this concept works well withthe concepts disclosed above related to rack location designs. Thisallows this information to flow without the use of physical cables.Furthermore, in this exemplary embodiment, an optical interconnectbetween units is created using the void spaces in the sides of the rack.This could also be realized in a fixed x-y location on the rack unit.

Referring to FIG. 5, a schematic diagram of a rack having a plurality ofoptical links communicating with each other is illustrated. The 42U rack50 of FIG. 5 includes at least a first unit 52 (1-4U) and a blank (ornon-supported) unit 54. Each unit of the rack 50 includes a receiver 56and a transmitter 58. Therefore, the rack 50 has a communication pathbetween the units in the rack 50.

The type of information that may be used in this type of communicationnetwork could be the rack location information as disclosed above, wherethe following information is passed from unit to unit.

Unit ID: Unique ID for a unit, e.g., model number+serial number.

Rack ID: the Unique ID from Unit 1 used as Rack ID.

Number of Us: the height of the Unit in Us.

Number of Blank Us: U location for first unit with this interface.

Unit number: of first unit with this interface.

U location: the location the unit starts at.

Number in the Rack: the unit number it is in the Rack.

Fault status: a fault status information being pass up.

This method is not limited to only this type of information. Theinformation is presented for illustrative purposes. One skilled in theart may use several different parameters and different values to achievesimilar results.

Referring to FIG. 6, a schematic diagram of how the optical links inFIG. 5 use void spaces in the sides of the rack is illustrated. Thesystem 60 includes a main unit 62, a pivot 64, a series of units 66, anda method of attaching the units 68. Each unit includes an LED orreceiver 70.

The main concern is that a standard rack is 19″ wide and that is allthat fits between the mounting strips at the front and back of the rack.But in between these mounts is void space. So the optical transmittersand receivers are placed on an arm that moves out of the way and springsback into its fixed location.

The methods of FIG. 6 involve: When a user places the unit into therack, the optical mount is pushed backwards into the unit, so that theunit can clear the mounting brackets. After the bracket has been clearedthe optional mount then moves back into its fixed location. The opticalmount is in the same physical location in each unit so that the opticaltransmitters and receivers align. The transmitters would tend to have awide angle to make up for tolerances in alignment. The optical armswould also be designed to block the light from the transmitter fromleaking upward. Also the transmitter and receiver would, be able to spana space to allow for blank spaces 54 in FIG. 5 or units that do notsupport this interface.

Referring to FIG. 7, a schematic diagram of another method of producingan optical link at a fixed x-y location in a unit is illustrated. Thesystem 80 includes a top unit 82, a bottom unit 84, a receiver 86, and atransmitter 88. The communication of data flows from the bottom unit 84to the top unit 82 of the rack.

Referring to FIG. 8, a schematic diagram where each rack and or opticalarm could have both a transmitter 92 and a receiver 93 on the top of theunit, and both a transmitter 94 and a receiver 91 on the bottom of theunit, so that communications could flow both ways (up and down therack), to support the loop method.

Referring to FIG. 8 the transmitter 92 and 94 and receiver 91 and 93pairs, can be used to determine the number of “Us” between the units.This is done by measuring the time for a signal to be sent between oneunit and back to the other.

The capabilities of the present invention can be implemented insoftware, firmware, hardware or some combination thereof.

As one example, one or more aspects of the present invention can beincluded in an article of manufacture (e.g., one or more computerprogram products) having, for instance, computer usable media. The mediahas embodied therein, for instance, computer readable program code meansfor providing and facilitating the capabilities of the presentinvention. The article of manufacture can be included as a part of acomputer system or sold separately.

Additionally, at least one program storage device readable by a machine,tangibly embodying at least one program of instructions executable bythe machine to perform tire capabilities of the present invention can beprovided.

While the preferred embodiment to the invention has been described, itwill be understood that those skilled in the art, both now and in thefuture, may make various improvements and enhancements which fall withinthe scope of the claims which follow. These claims should be construedto maintain the proper protection for the invention first described.

1. A method for automatically determining a physical location of one ormore units in a rack, the method comprising: using one or more physicalcables between rack units; cascading a first signal through the one ormore units located in the rack encoded with at least one unit numberparameter and at least unit height parameter; and creating a rack ID byutilizing hardware parameters, the hardware parameters being determinedby: detecting a second signal passed from a bottom unit, the bottom unitlocated at the bottom of the rack; and using a third signal to send databetween the one or more units in the rack by manipulating void spaceswithin the sides of the rack, the third signal being either cabled or anoptical signal.
 2. The method of claim 1, wherein each of the one ormore units includes an optical transmitter and a receiver.
 3. The methodof claim 1, wherein the data includes: a Unit ID, the rack ID, a numberof units, a number of blank units, a unit location, the unit number, anda fault status of each of the one or more units.
 4. The method of claim1, wherein the one or more units include arms that use voids in the sideof the racks for optical communication.
 5. The method of claim 1,wherein the one or more units are located at fixed locations for opticalcommunication.
 6. A system comprising: a rack having one or more unitsfor automatically determining a physical location of the one or moreunits within the rack by implementing the steps of: using one or morephysical cables between rack units; cascading a first signal through theone or more units located in the rack encoded with at least one unitnumber parameter and at least unit height parameter; and creating a rackID by utilizing hardware parameters, the hardware parameters beingdetermined by: detecting a second signal passed from a bottom unit, thebottom unit located at the bottom of the rack; by manipulating voidspaces within the rack; and using a third signal to send data betweenthe one or more units in the rack by manipulating void spaces within thesides of the rack, the third signal being either cabled or an opticalsignal.
 7. The system of claim 6, wherein each of the one or more unitsincludes an optical transmitter and a receiver.
 8. The system of claim6, wherein the data includes: a Unit ID, the rack ID, a number of units,a number of blank units, a unit location, the unit number, and a faultstatus of each of the one or more units.
 9. The system of claim 6,wherein an interconnect between the rack units is optical.
 10. Thesystem of claim 6, wherein the optical transmitter and the receiver areused to determine a number of blank units or a number of non-supportingunits between the one or more units located in the rack.
 11. The systemof claim 6, wherein the one or more units include arms that use voids inthe side of the racks for optical communication.
 12. The system of claim6, wherein the one or more units are located at fixed locations foroptical communication.
 13. A method for optically connecting one or moreunits within a rack, the method comprising: cascading a first signalthrough the one or more units located in the rack encoded with at leastone unit number parameter and at least unit height parameter; andcreating a rack ID by utilizing hardware parameters, the hardwareparameters being determined by: detecting a second signal passed from abottom unit, the bottom unit located at the bottom of the rack; andusing a third signal to send data between the one or more units in therack by manipulating void spaces within the rack, the third signal beingeither cabled or an optical signal; wherein the one or more unitsinclude arms that use the void spaces in the side of one or more racksfor optical communication or wherein the one or more units are locatedat fixed locations for optical communication.